The Renesas PS2761B-1Y-V-F3-A is a single-channel, DC-input, transistor-output optocoupler in a gull-wing package (4-SOP). It provides 3750Vrms galvanic isolation between input and output, making it a straightforward choice for breaking ground loops and protecting low-voltage logic from high-side transients in industrial power supplies, motor drives, PLC I/O modules, and isolated sensor interfaces. The output transistor is rated for 50mA continuous current and a 70V collector-emitter breakdown, so it can drive a small relay coil, a logic-level input, or a gate driver directly in many designs without an external buffer.
The 3750Vrms isolation rating is the one-minute withstand voltage between input LED and output phototransistor. In a 240VAC motor drive or a 48V telecom rectifier, that margin comfortably exceeds the peak transient the barrier sees during a surge event, assuming basic insulation coordination. For reinforced insulation in mains-connected equipment, you would typically need 5000Vrms or more, so this part is best suited for functional or basic isolation layers.
Current transfer ratio — sizing the LED drive
The CTR is specified at 50% minimum and 400% maximum at a forward current of 5mA. That wide spread means the designer must size the input resistor so the output transistor saturates at the worst-case low CTR.
Switching speed — 4µs rise, 5µs fall
That is fine for 50/60 Hz mains zero-cross detection, relay drive, or low-speed isolated serial links (UART up to 115200 baud). For higher-speed isolated communication like SPI or CAN, you would reach for a digital isolator or a faster optocoupler.
Package and mounting — 4-SOP gull-wing
The part comes in a gull-wing package (4-SOP), surface-mount only. The gull-wing leads are visible for inspection and rework-friendly with hot air.
It is ROHS3 compliant. The NEPOC series from Renesas has a long production history, and the PS2761B base part number is shared across several CTR and package variants, which suggests ongoing die availability.